BEIJING (AP) — Pandemic lockdowns are expanding across China, including in a city where factory workers clashed this week with police, as the number of COVID-19 cases hits a daily record.

Residents of eight districts of Zhengzhou, home to 6.6 million people, were told to stay home for five days beginning Thursday except to buy food or get medical treatment. Daily mass testing was ordered in what the city government called a “war of annihilation” against the virus.

During clashes Tuesday and Wednesday, Zhengzhou police beat workers protesting over a pay dispute at the biggest factory for Apple’s iPhone, located in an industrial zone near the city. Foxconn, the Taiwan-based owner of the factory, apologised Thursday for what it called “an input error in the computer system” and said it would guarantee that the pay is the same as agreed to and in official recruitment posters.

In the previous 24 hours, the number of new COVID cases rose by 31,444, the National Health Commission said Thursday. That’s the highest daily figure since the coronavirus was first detected in the central Chinese city of Wuhan in late 2019.

The daily caseload has been steadily increasing. This week, authorities reported China’s first COVID-19 deaths in six months, bringing the total to 5,232.

While the number of cases and deaths is relatively low compared to the US and other countries, China’s ruling Communist Party remains committed to a “zero-COVID” strategy that aims to isolate every case and eliminate the virus entirely. Most other governments have ended anti-virus controls and now rely on vaccinations and immunity from past infections to help prevent deaths and serious illness.

Businesses and residential communities from the manufacturing center of Guangzhou in the south to Beijing in the north are in various forms of lockdowns, measures that particularly affects blue-collar migrant workers. In many cases, residents say the restrictions go beyond what the national government allows.

Guangzhou suspended access Monday to its Baiyun district of 3.7 million residents, while residents of some areas of Shijiazhuang, a city of 11 million people southwest of Beijing, were told to stay home while mass testing is conducted.